Formal Report
UNU EDC Monitoring in the Philippines
Submitted by: Dr. Evangeline C. Santiago
July, 2002-Mar, 2003
- Introduction:
Samples of sediments and fresh water were collected in two river systems in the Philippines and were analyzed for Aldrin, Dieldrin, Endrin, DDT, Heptachlor, and Chlordane as planned for the regional monitoring for this year. The seven pesticides (including HCB which was not investigated because of unavailability of standard) planned for this year’s monitoring are among the POPs chemicals to be monitored as recommended by the Stockholm Convention. The information on the levels of these POPs pesticides in two new areas of study selected for this year will add to the dearth of information on the inventory of POPs pesticides in the country. Heptachlor Epoxide, Endrin Aldehyde, Endrin Ketone, and the metabolites of DDT, Endosulfan, Transnonachlor, Methoxychlor and Mirex were also determined in the samples. Monitoring of Endrin, Endosulfan and Methoxychlor are relevant because these organochlorine pesticides may still be found in significant amounts in the farm areas. The inclusion of residues of the metabolites of pesticides in the monitoring activity, on the other hand, could give important information that can help environmental scientists in assessing the continued impacts of the organochlorine pesticides in the Philippine environment.
- Sampling Procedures
2.1 Selection of Location
The river systems of two major agricultural provinces with important fisheries industry but with contrasting topology in Luzon were selected for the study. The study areas and the sampling sites are shown in Fig.1.
Pangasinan is a province situated in the central plain of Luzon and its river system is composed of three big rivers and tributaries that catch the water from surrounding mountainous areas of Zambales, Mountain Province and Nueva Ecija. Mountain Province is the primary vegetable and flower producer in the country and may be a n important contributor of pesticide residues in the river waters in Pangasinan. Since Pangasinan is a vast plain with abundant water supply, agriculture is a major industry in the province. In addition to agriculture, fishery is also a major industry in the western part of the province because of the wide coastal area that receives the outflows of the rivers. The coastal towns of Dagupan, Lingayen, Binmaley and Bonoan have large fishponds and are important sources of fish supply in Luzon. Sediment and water samples from seven sampling sites across the whole river system were collected for analysis.
Laguna province is located south of Metro Manila and is actually situated at the foot of mountain ranges of Makiling and lower Sierra Madre. At the center of the province is Laguna Lake, considered one of the biggest lakes in Asia, which acts as reservoir of water from a number of small rivers originating from the mountains. Laguna Lake is also a major source of freshwater fish in Luzon. Different types of fruit trees are planted in the higher terrain of some parts of Rizal province adjacent to Laguna rice and vegetables are grown in the lower terrain in Laguna Province. Ten samples of water and sediments from the rivers in Laguna were collected for analysis. The information that monitoring of the organochlorine pesticides in the river systems will generate would not only provide the actual levels of the residues but would also indicate the influence of the character of the river systems to the levels of the pesticide residues. Further monitoring studies that can be done in the future on the coastal areas in Pangasinan and in Laguna Lake could provide a better understanding of the factors that affect the levels of pesticide residues in the fisheries areas and the possible impact on the health of the consumers of the fish that are grown in the areas.
2.2 Conditions During Sample Collection
Sampling was done for two periods, the fist sampling in September, 2002 and the second sampling in January, 2003. Table 1 shows the details of the exact location of the sampling sites and the weather conditions during sampling. Figures 2a and 2b show some river sites in Laguna/Rizal and Pangasinan respectively.
- Analytical Results:
3.1 Summary of Results
For water samples collected on the first sampling, the method used was the old UNU-1 Method (liquid/liquid extraction and clean-up in silica gel cartridge). For the samples collected on the second sampling, the method used was the UNU-2 Method (liquid /liquid extraction after filtration, extraction of filter but clean-up using silica cartridge).
For sediment samples, the US EPA method involving Soxhlet extraction of wet sample dried with sodium sulphate, removal of sulfur by activated copper treatment, and clean-up by silica column was employed.
A. Water Samples
Table 2a shows the results for the water samples collected during the first and second samplings.
During the first and second samplings, gamma BHC, aldrin, gamma chlordane, alpha chlordane dieldrin and DDT were detected in some Laguna river sites at very low levels about the estimated method detection limits. Endrin Aldehyde, Endrin Ketone, Endosulfan and the metabolites of DDT were also detected at levels about the detection limits in some Laguna sites. The samples collected during the second sampling in all Laguna sampling sites except at Bay and Morong showed significant to high levels of Dieldrin in the range of 0.031-0.127 ppb. Endrin Aldehyde was detected near the estimated detection level at 0.15 ppb and 0.25 ppb in Tanay and Bay respectively, other sites showed Endrin Aldehyde at levels much lower than the estimated detection limit.
During the first sampling, Aldrin was detected in most Pangasinan sites with significant levels of 0.108 ppb, 0.061 ppb and 0.063 ppb noted in Calasiao, Embarcadero and Mapandan towns. Gamma Chlordane, Endrin Aldehyde,Dieldrin and some DDT metabolites were detected in most sampling sites at lower than the estimated detection limits. The samples obtained during the second sampling showed high levels of Dieldrin in the range of 0.043-0.094 ppb in all the Pangasinan sites. Aldrin was also detected in all sampling sites but in much lower levels than those found during the first sampling. Gamma and Alpha Chlordanes were detected at detection limit levels. Endrin Aldehyde was also detected in significant concentration of 0.267 ppb in Urbiztondo.
It is significant to note that Dieldrin was commonly detected in significant concentration in most rivers in Laguna and all river sites in Pangasinan during the second sampling. This may be due to the concentration effect of the drier rivers at this sampling period. However, it may also be due to recent usage of the pesticide since the sampling was done at the early stage of the second planting season. The analysis of sediments for the second sampling period would have been helpful in interpreting the results, unfortunately, the laboratory was not able to do the analysis.
B. Sediment Samples
Only the results for the first sampling are reported. Table 2b shows the concentrations of OCPs from the sediment samples. In both sampling sites, Endrin and its metabolites, Gamma BHC and Methoxychlor were detected in significant concentrations. The sediments in Laguna showed much higher levels of Endrin and its metabolites, Dieldrin and Methoxychlor than the sediments in Pangasinan, but Gamma BHC were detected in higher amounts in Sinocalan River at Calasiao and Bued River in San Vicente in Pangasinan.
3.2 Summary of Quality Control Assurance Measures
A. Water Samples
Samples were collected in duplicate. For the first sampling, some duplicate samples were analyzed for the pesticides. For the second sampling, because of time limitation, the results for only one set of samples could be included in this report.
One reagent blank sample is included for every batch of analysis of 5-6 samples from the first sampling. An estimate of the Method Detection Limit for the analysis method (UNU-1 Method) used for the samples was based on the standard deviation of the results of 5 blank samples. For the analytes that gave zero standard deviation, the MDL was estimated based on the minimum concentration of the analyte in the calibration curve. Each sample was spiked with 100ng tetrachloro-m-xylene and Decachlorobiphenyl to check recovery. The estimate of the MDL for the method (UNU-2 Method) was not done.
Tables 3a and 3b show some data pertinent to quality control of analysis of the samples collected in the first sampling.
B. Sediment Samples
One reagent blank was analyzed for each batch of samples analyzed. Some duplicate samples taken at random were analyzed. Table 3c shows the standard deviation of the results for the duplicate samples.
3.3 Problems Encountered
No unusual problems were encountered this time, except the late timing of the training course for the UNU-2 Method and QA/QC/ interlab comparison exercise. Two methods of analysis were employed for this monitoring activity and the contribution of the difference in the methods to the results of the samples could not be assessed because of time limitations.
- Conclusion:
Aldrin, Gamma Chlordane, Gamma BHC, Dieldrin and Endrin Aldehyde were detected at lower than the estimated detection levels (0.001-0.005 µg/L) in the water samples in Laguna/Rizal and Pangasinan rivers during the two sampling periods. These pesticides were also found in the sediments. Dieldrin (up to 0.12 µg /L) was detected in some river sites in both study areas during the second sampling.
The monitoring activities showed that some residues of OCPs can be detected in river water samples, however, some efforts should still be done to determine if the low levels that were detected are significant to mean presence of residues or can be attributed to analytical error.
The monitoring of OCPs in the sediment samples showed high concentrations of OCPs with some above the threshold concentrations for the protection of certain aquatic organisms according to NOAA screening criteria of contaminated sediments. The higher concentration of OCPs in the sediments from Laguna rivers than those of Pangasinan rivers could be due to the slower water current in the smaller rivers in Laguna.
Figure 1. Study Area and Sampling Points for UNU Monitoring Project Phase 2
Table 3c Average Concentrations and Standard Deviation of OCPs in Duplicate Sediment Samples Collected During the First Sampling
|
|
Concentration, ng/g dry weight |
|||||||
|
OCPs |
LL2-1 |
LL2-2 |
LL2,ave |
LL2 std dev |
LL4-1 |
LL4-2 |
LL4.ave |
LL4,std dev |
|
Beta BHC |
ND |
ND |
ND |
ND |
ND |
ND |
ND |
|
|
Gamma BHC |
37.31 |
0.00 |
18.65 |
26.38 |
3.70 |
6.93 |
5.31 |
2.28 |
|
Delta BHC |
ND |
ND |
ND |
|
ND |
ND |
ND |
|
|
Heptachlor |
0.00 |
0.44 |
0.22 |
0.31 |
ND |
ND |
ND |
|
|
Aldrin |
ND |
ND |
ND |
|
5.12 |
0.00 |
2.56 |
3.62 |
|
Heptachlor Epoxide |
ND |
ND |
ND |
|
ND |
ND |
ND |
|
|
Gamma Chlordane |
1.14 |
1.14 |
1.14 |
0.00 |
3.28 |
1.61 |
2.45 |
1.18 |
|
Endosulfan1 |
ND |
ND |
ND |
|
4.96 |
0.00 |
2.48 |
3.50 |
|
Alpha Chlordane |
0.00 |
0.20 |
0.10 |
0.14 |
1.78 |
0.00 |
0.89 |
1.26 |
|
Transnonachlor |
ND |
ND |
ND |
|
2.84 |
0.00 |
1.42 |
2.01 |
|
Dieldrin |
4.01 |
0.00 |
2.00 |
2.83 |
5.64 |
0.47 |
3.06 |
3.65 |
|
2,4, DDD |
0.35 |
0.09 |
0.22 |
0.18 |
0.00 |
0.60 |
0.30 |
0.42 |
|
Endrin |
7.76 |
66.76 |
37.26 |
41.72 |
0.00 |
23.05 |
11.53 |
16.30 |
|
Endosulfan2 |
ND |
ND |
ND |
|
2.97 |
0.00 |
1.48 |
2.10 |
|
4,4' DDD |
0.17 |
0.20 |
0.18 |
0.03 |
0.18 |
0.00 |
0.09 |
0.12 |
|
2,2' DDT |
0.21 |
0.00 |
0.10 |
0.15 |
0.00 |
1.15 |
0.57 |
0.81 |
|
Cis Nonachlor |
ND |
ND |
ND |
|
0.00 |
0.26 |
0.13 |
0.18 |
|
Endrin Aldehyde |
0.37 |
8.89 |
4.63 |
6.03 |
1.22 |
6.20 |
3.71 |
3.52 |
|
4.4' DDT |
0.00 |
0.19 |
0.09 |
0.13 |
0.85 |
0.41 |
0.63 |
0.31 |
|
Endrin Ketone |
0.00 |
32.47 |
16.23 |
22.96 |
5.22 |
0.00 |
2.61 |
3.69 |
|
Methoxychlor |
ND |
ND |
ND |
|
13.83 |
0.00 |
6.91 |
9.78 |
|
Mirex |
ND |
ND |
ND |
|
0.06 |
0.00 |
0.03 |
0.04 |
|
OCPs |
LL5-1 |
LL5-2 |
LL5.ave |
LL5,std dev |
LL7-1 |
LL7-2 |
LL7.ave |
LL7,std dev |
|
Beta BHC |
ND |
ND |
ND |
|
ND |
ND |
ND |
|
|
Gamma BHC |
1.94 |
0.00 |
0.97 |
1.37 |
1.10 |
0.00 |
0.55 |
0.78 |
|
Delta BHC |
ND |
ND |
ND |
|
ND |
ND |
ND |
|
|
Heptachlor |
8.63 |
0.79 |
4.71 |
5.55 |
0.00 |
0.42 |
0.21 |
0.30 |
|
Aldrin |
14.21 |
0.00 |
7.10 |
10.05 |
4.61 |
0.00 |
2.31 |
3.26 |
|
Heptachlor Epoxide |
ND |
ND |
ND |
|
ND |
ND |
ND |
|
|
Gamma Chlordane |
0.00 |
2.38 |
1.19 |
1.69 |
0.00 |
1.64 |
0.82 |
1.16 |
|
Endosulfan1 |
ND |
ND |
ND |
|
2.97 |
0.00 |
1.49 |
2.10 |
|
Alpha Chlordane |
ND |
ND |
ND |
|
0.10 |
0.00 |
0.05 |
0.07 |
|
Transnonachlor |
4.29 |
0.00 |
2.14 |
3.03 |
ND |
ND |
ND |
|
|
Dieldrin |
3.08 |
0.81 |
1.94 |
1.60 |
ND |
ND |
ND |
|
|
2,4, DDD |
0.76 |
0.00 |
0.38 |
0.54 |
ND |
ND |
ND |
|
|
Endrin |
0.00 |
177.57 |
88.78 |
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